
public class Test19092301 {
	public static void main(string[]args) {
        Scanner scanner=New Scanner(System.in);
		    int F = scammer.nextInt();
		    	float c;
		    c=(F-32)*5/9;
		    System.out.orintf("%.4f",c);
		    soanner.(losec);
		    import  
	}

}
